News Analysis The abortion drug RU-486 is not like most drugs that chug through Australia's regulatory system.

Rarely has the availability of a drug been tied to such charged emotions, including headlines that warn of backyard miscarriages for desperate women.

Part of the debate, which is due to come to a head in a parliamentary vote later this week, relates to the drug's safety and efficacy.

Does RU-486, otherwise known as Mifeprex or mifepristone, have side-effects? And how does it compare with surgical abortions?

Under the current system, the conservative, Catholic, anti-abortion health minister Tony Abbott, has the final say on the drug.

But advocates of RU-486 say that decision should rest solely with health experts at the Therapeutic Goods Administration, as it does for other drugs in Australia.

Heated debate

RU-486 was developed in France in the 1980s and is used for terminating a pregnancy at less than nine weeks.

Sexual Health and Family Planning Australia says RU-486 has been used by more than 21 million women around the world and is available in 35 countries, including the UK, US, New Zealand, France, Sweden, Greece and Spain.

The drug works by blocking the effects of the hormone progesterone, which a woman needs to start and maintain a pregnancy.

It breaks down the lining of the uterus, which can no longer hold onto the fertilised egg.

Usually, the woman has to return to her doctor two days later for a prostaglandin, a drug that causes her uterus to contact and expel the products of conception.

How safe is it?

Associate Professor Anne Tonkin, a clinical pharmacologist from the University of Adelaide and a drug adviser to the federal government, says:

"Mifepristone ... is not a risky drug, and is not a particular threat to women's safety. It is not a poison or a toxin, and has very few side-effects.

"It works by mimicking a common cause of natural miscarriage. The side-effects are the same as those of a spontaneous natural abortion, and include bleeding as part of the normal response."

She says that in 95% of cases, a miscarriage induced by mifepristone used in combination with a prostaglandin requires no further treatment.

"In about 5%, as is the case for natural miscarriage, a minor surgical procedure is required to complete the abortion. This means that 95% of women who would otherwise have required an operative procedure could avoid it with the use of mifepristone," she says.

But a study that looked at all side-effects of the drug reported to the US Food and Drug Administration over a four-year period found there were serious effects.

These included four otherwise healthy women who had died from bleeding or septic shock after taking the drug, the most common side-effects reported by all women.

Of the 607 adverse events analysed in the February issue of the Annals of Pharmacotherapy, there were women who reported foetal abnormalities that appeared after failed abortion attempts, ruptured ectopic pregnancies and allergic reactions.

Emergency access

Chief medical officer Professor John Horvath has been concerned about the risks of later side-effects in some women who take the drug.

In written advice to the health minister on the safety for women in remote areas, he says RU-486 "carries a significantly higher risk [than surgical abortion] of later adverse events".

And he says that if doctors are not supported by services that could deal with emergency complications out of hours, this would "substantially increase the risks to women undergoing termination".

Another recent study, published in the journal Contraception, concludes the "safety of mifepristone is high".

When it analysed the results from more than 95,000 RU-486 abortions in the US, it found few serious medical complications in everyday use.

Some 2.2 per 1000 women had a complication, most commonly heavy bleeding. And 1.1 per 100,000 women died after taking the drug.

By comparison, the mortality rate from surgical abortion was 1 per 100,000 women.

Others have argued that rather than debating which abortion method is best, the aim of the current debate is to offer women a choice.